Conventional shiftable transmissions use gears and splines incorporating backlash so that the transmission can be shifted. This backlash causes error and downgrades the ability to determine or hold position of the output shaft of the transmission. Various attempts have been made to solve the problems arising as the result of backlash in simple gear sets. Such attempts don't adapt will to shiftable transmissions and result in complex devices that have not been successful.
In industries such as the automated machine tool industry, it is important to be able to determine and hold position of a transmission output shaft via its input shaft, and to make every effort to reduce the effects of backlash. The cost of down time to repair or exchange splined components and gears is monumental in an installation such as an automated production line in the automotive industry.